This application claims the priority of Korean Patent Application No. 2002-35140, filed 22 Jun., 2002 in the Korean Intellectual Property Office, which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to an apparatus and method of allowing Internet-enabled information terminals to be directly connected to the Internet without setting a user in a subnet network, and more particularly, to an apparatus and method of automatically searching for a Domain Name System (DNS) server in an outernet for a network in which a DNS server is not present.
2. Description of the Related Art
When the address of a server using the Internet Protocol version 6 (IPv6) is obtained using the existing Dynamic Host Configuration Protocol (DHCP) method, a DHCP server sends the address together with information regarding a DNS server. Therefore, the address of the DNS server can be obtained during allocation of an information provider via the DHCP server. The DHCP refers to a protocol that enables central management and allocation of Internet Protocol (IP) addresses of network managers in a network of an organization. According to the Transmission Control Protocol/Internet Protocol (TCP/IP) of the Internet, only a computer having an inherent IP address can connect to the Internet. That is, each computer user belonging to an organization shall be allocated an identification IP address for his/her computer so as to connect to the Internet. Unless the DHCP method is used, an IP address must be manually input to each computer, and if a computer is moved to a different place connected to the network, the computer must be allocated with a new IP address. The DHCP method enables central management and allocation of IP addresses of a network manager, and automatic transmission of a new IP address to a computer moved to a different place connected to the network. The DNS is a system for changing the name of an Internet domain into its identification IP address that is used to detect the location of the Internet domain in the Internet. The name of an Internet domain refers to its Internet address allowing users to easily detect and remember the Internet domain. A digital IP address is required to detect the location of a computer on the Internet. The DNS server holds a database regarding domain names and their corresponding IP addresses and provides them to a computer requiring the database. When an IPv6 address is automatically created using a stateless address autoconfiguration method, a router in the same link periodically reports DNS information, and thus, the address of the DNS server can be obtained from the DNS information.
However, when an IPv6 address is automatically created using the conventional stateless address autoconfiguration method, it is impossible to automatically obtain the address of a DNS server using the conventional method if a DNS server is not present in a subnet. In other words, during autoconfiguration of the IPv6 address, the address of a DNS server can be easily detected using the conventional method only when the DNS server is present within a subnet.